388 



C. SKOTTSBERG 



o{ Nothofagus. Age proposed by BERRY [334) Lowest Miocene or Upper Oligocene, 

 then younger than the Magallanes flora. 



The Magallanes flora. — Dus^N (/p) distinguished two plant-bearing horizons, 

 an upper Araucaria horizon and a lower Nothofagus horizon. Of the remaining 

 dicotylous genera none were identified with living ones; DUSEN preferred to call 

 them EscalloniipJiylluJJi, Hydrangeipliylluvi etc. There is no obviously tropical 

 element, it is a temperate flora. DuSEN regarded the two horizons as distinctly 

 different in age, dating the upper to Lower Miocene, the lower to, perhaps, 

 Oligocene. BERRY, who doubted the correctness of this distinction, regarded them 

 as older than the Concepcion-Arauco flora, which seems improbable. 



The Seymour flora. — To judge from DusEn's description [80) the tropical 

 element is not conspicuous, whereas the actual South Chilean forest flora is well 

 represented: Araucaria (nearly related to A. araiicana), Drimys, Nothofagus, 

 Caldclu/'ia, Laurelia, Lomatia, all supposed to be of Antarctic parentage; I can 

 see little reason for Berry's assertion that the Seymour flora contains "a large 

 element of subtropical or warm temperate types like those found to-day in south- 

 ern Brazil" together with "another large element of forms suggestive of the 

 existing temperate flora of Southern Chile and Patagonia"; the former was sub- 

 tropical and coastal, the latter temperate and montane, washed down, DUS^N 

 thought, from the mountains and embedded together with the leaves of the low- 

 land trees. The age was estimated to be Upper Eocene. Florin's discovery of a 

 species of Acnwpyle [Phyllltes sp., Dusen) is of particular interest [338). 



We have seen that Berry considered the XotJiofagns beds to be older than 

 the Arauco-Pichileufu deposits. All the local fossil floras of Patagonia are, he 

 says (jjj), older than the marine Patagonian transgression and undoubtedly pre- 

 Miocene. Frenguelli distinguished three epochs : (a) Late Cretaceous to early 

 Eocene, with a tropical flora, known from the Chalia beds; (b) an intermediate 

 period with subtropical and temperate types [NotJiofagiis) mixed; to this he would, 

 I suppose, refer the Seymour flora; (c) the youngest epoch, Miocene-Pliocene, 

 evidently extending into Pleistocene: a temperate flora, now ranging along both 

 sides of the southern Andes and characterized by the dominance of Nothofagus 

 and of a number of conifers. The more or less corresponding development of 

 the Andes was according to BERRY [^28): (i) Eocene-early Miocene: low relief, 

 no high continuous mountains, followed by (2) a period of great uplift; {3) late 

 Miocene to early Pliocene: mature erosion, low relief; (4) late Pliocene to Pleis- 

 tocene: extensive uplift, beginning of the formation of the Chilean and Peruvian 

 deeps, where earlier there was land; (5) submergence of the coastal plain. Finally, 

 but not mentioned by Berry, the series of glacial and interglacial periods, a 

 most important factor of disturbance. 



This is the background against whicli we have to discuss the history of the 

 Juan Fernandez flora. 



